Describe the bug
When you have two agents in sequence, in this case in a LoopAgent, the second agent is often unable to see items stored in the state of the previous agent.

To Reproduce
This has been hard to replicate as a timing issue, but seems to be OK on smaller prompts, but more noticable on a larger prompt.

e.g

graph_builder1 = LlmAgent(
    name="GraphBuilder1",
    model=LLM_MODEL1,
    generate_content_config=types.GenerateContentConfig(
        temperature=0.2
    ),
    instruction=GENERATE_KG_PROMPT.format(knowledge_graph_key="knowledge_graph1"),
    tools=[store_knowledge_graph],
    output_key='knowledge_graph1',
)

graph_reviewer1 = LlmAgent(
    name="GraphReviewer1",
    model=LLM_MODEL2,
    instruction=REVIEW_PROMPT.format(knowledge_graph_key="knowledge_graph1"),
    tools=[validate_turtle, load_knowledge_graph], # <--- can't find key knowledge_graph1
)

kg_refinement_loop1 = LoopAgent(
    name="KGRefinementLoop1",
    max_iterations=5,
    sub_agents=[
        graph_builder1,
        graph_reviewer1,
        StopIfComplete(name="StopChecker1", status_key="graph_status1"),
    ],
)

from: https://github.com/hammertoe/GraphCycle/blob/main/graphcycle/agent.py#L220C1-L235C2

**Expected

**
A subsequent agent should be able to reliably access state keys from the previous agent

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Darwin Matts-MacBook-Pro-2.local 23.6.0 Darwin Kernel Version 23.6.0: Thu Mar 6 22:01:15 PST 2025; root:xnu-10063.141.1.704.6~1/RELEASE_ARM64_T6000 arm64
• Python version(python -V): Python 3.13.3
• ADK version(pip show google-adk): 1.1.1

Additional context
Like I said, a timing issue... so intermittent. Seems like the second agent is starting before the first has finished saving state or something.